Search Results (3)

The marine unicellular red alga Rhodosorus marinus is a promising source of the valuable phycobiliprotein phycoerythrin and essential omega-3 polyunsaturated fatty acids (PUFAs), yet the environmental triggers for their optimal co-production remain to be fully elucidated. This study was conducted to investigate the effects of thermal and photic stress in terms of maximizing the yield of these high-value bioactive compounds. R. marinus was cultivated under a range of temperatures (18–24 °C) and light intensities (100–335 µmol photons m⁻² s⁻¹) to assess its physiological and biochemical responses, particularly focusing on lipid accumulation. This study investigates the effects of thermal (18–24 °C) and photic (100–335 µmol photons m⁻² s⁻¹) stress on the concurrent production of the valuable phycobiliprotein, phycoerythrin (PE), and essential omega-3 polyunsaturated fatty acids (PUFAs) in the marine red microalga Rhodosorus marinus. Fatty acid profiles were quantified using gas chromatography (GC), while pigment content was assessed via spectrophotometry. Statistical analyses, including one-way ANOVA and Tukey’s post hoc test, were employed to determine the significance of environmental effects. Our results demonstrate that a mild hypothermic condition of 18 °C significantly enhanced the production of eicosapentaenoic acid (EPA) compared to higher temperatures. Conversely, cell density was maximized at 22 °C. Under the 18 °C thermal regime, lower light intensities (100–185 µmol photons m⁻² s⁻¹) promoted a superior synthesis of both bioactive lipids and pigments. In conclusion, the strategic application of mild hypothermia combined with moderate light intensity is an effective approach to substantially boost the metabolic yield of high-value compounds in R. marinus, highlighting its potential as a sustainable source for nutraceutical and pharmaceutical applications. Full article

Optical Camera Communication (OCC) systems have a potential application in microalgae production plants. In this work, a proof-of-concept prototype consisting of an artificial lighting photobioreactor is proposed. This reactor optimises the culture’s photosynthetic efficiency while transmitting on-off keying signals to a rolling-shutter camera. Upon reception, both signal decoding and biomass concentration sensing are performed simultaneously using image processing techniques. Moreover, the communication channel’s theoretical modelling, the data rate system’s performance, and the plant distribution requirements and restrictions for a production-scale facility are detailed. A case study is conducted to classify three different node arrangements in a real facility, considering node visibility, channel capacity, and space exploitation. Finally, several experiments comprising radiance evaluation and Signal-to-Noise Ratio (SNR) computation are performed at different angles of view in both indoor and outdoor environments. It is observed that the Lambertian-like emission patterns are affected by increasing concentrations, reducing the effective emission angles. Furthermore, significant differences in the SNR, up to 20 dB, perceived along the illuminated surface (centre versus border), gradually reduce as light is affected by greater dispersion. The experimental analysis in terms of scattering and selective wavelength attenuation for green (Arthrospira platensis) and brown (Rhodosorus marinus) microalgae species determines that the selected strain must be considered in the development of this system. Full article

The aim of the present study was to investigate the neuro-soothing activity of a water-soluble hydrolysate obtained from the red microalgae Rhodosorus marinus Geitler (Stylonemataceae). Transcriptomic analysis performed on ≈100 genes related to skin biological functions firstly revealed that the crude Rhodosorus marinus extract was able to significantly negatively modulate specific genes involved in pro-inflammation (interleukin 1α encoding gene, IL1A) and pain detection related to tissue inflammation (nerve growth factor NGF and its receptor NGFR). An in vitro model of normal human keratinocytes was then used to evaluate the ability of the Rhodosorus marinus extract to control the release of neuro-inflammation mediators under phorbol myristate acetate (PMA)-induced inflammatory conditions. The extract incorporated at 1% and 3% significantly inhibited the release of IL-1α and NGF secretion. These results were confirmed in a co-culture system of reconstructed human epithelium and normal human epidermal keratinocytes on which a cream formulated with the Rhodosorus marinus extract at 1% and 3% was topically applied after systemic induction of neuro-inflammation. Finally, an in vitro model of normal human astrocytes was developed for the evaluation of transient receptor potential vanilloid 1 (TRPV1) receptor modulation, mimicking pain sensing related to neuro-inflammation as observed in sensitive skins. Treatment with the Rhodosorus marinus extract at 1% and 3% significantly decreased PMA-mediated TRPV1 over-expression. In parallel with these biological experiments, the crude Rhodosorus marinus extract was fractionated by centrifugal partition chromatography (CPC) and chemically profiled by a recently developed ¹³C NMR-based dereplication method. The CPC-generated fractions as well as pure metabolites were tested again in vitro in an attempt to identify the biologically active constituents involved in the neuro-soothing activity of the Rhodosorus marinus extract. Two active molecules, namely, γ-aminobutyric acid (GABA) and its structural derivative GABA-alanine, demonstrated a strong capacity to positively regulate skin sensitization mechanisms related to the TRPV1 receptors under PMA-induced inflammatory conditions, therefore providing interesting perspectives for the treatment of sensitive skins, atopia, dermatitis, or psoriasis. Full article